1. Field of the Invention
The present invention relates to an image forming apparatus such as copiers, facsimiles, printers and plotters. In addition, the present invention also relates to a complex image forming apparatus having two or more of copying, facsimiling, printing and plotting functions.
2. Discussion of the Background
Cavity type image forming apparatuses, in which a copy tray configured to receive and store copy sheets is formed on an upper surface of a main body serving as an image forming section, and an image reading section configured to read images of original documents is located over the copy tray with a space (i.e., cavity) therebetween, have been used for copiers, facsimiles, printers and plotters. For example, published unexamined Japanese patent applications Nos. (hereinafter referred to as JP-A) 05-219308 and 2005-167801 have disclosed such cavity type image forming apparatuses. In general, such cavity type image forming apparatuses have an advantage of space-saving, but have drawbacks such that the copy sheets on the copy tray cannot be well observed by operators (i.e., the visibility of the copy sheets is bad), and poor discharge properties such that jamming of the copy sheets tends to occur at the copy tray, and a large amount of copy sheets cannot be stored in the copy tray.
JP-A 2005-167801 discloses a cavity type image forming apparatus having configuration-such that the upper unit (i.e., image reading section or scanner) of the image forming apparatus can be opened while pivoted so that the consumable supplies such as process cartridges and transfer units in the main body can be replaced with new ones. The image forming apparatus has the following drawbacks:    (1) Since the upper unit extends toward the exit of the copy tray, the visibility of the copy sheets on the copy tray (hereinafter referred to as copy visibility) is bad.    (2) When replacing the process cartridge and/or transfer unit, the copy tray has to be opened after opening the upper unit, wherein the copy tray and the upper unit have different pivot axes. Thus, the image forming apparatus has complex configuration. Since the transfer unit is pivoted together with the pivoted unit, it is necessary to open the unit at a high angle to replace the consumable supplies.    (3) Since the exit of the copy tray is positioned on a relatively high level and the flat surface of the copy tray is located on a relatively low level while the upper unit extends toward the exit of the copy tray, the copy visibility is bad.    (4) When replacing the toner bottle, the upper unit and the copy tray have to be pivoted. In addition, the gap between the surface of the copy tray and the upper surface of exit of the copy tray is small, and therefore a large amount of copy sheets cannot be stored on the copy tray. Further, the copy sheets cannot be well observed from the front side of the image forming apparatus.    (5) Although the upper unit can be slid to replace the toner bottle, the copy visibility cannot be improved thereby.    (6) The scanner is easily pivoted and opened when receiving an upward force.    (7) The image forming apparatus uses a number of parts such as slide rails and rollers, resulting in increase of the manufacturing costs.    (8) There is a risk such that operator's fingers are wedged between the scanner and the image forming when the scanner is slid.
JP-A 05-219308 (i.e., Japanese patent No. 3176411) discloses a cavity type image forming apparatus in which a scanner is arranged over a copy tray. Therefore, the copy visibility is not good. In order to improve the copy visibility, the scanner is slid to the rear side. Since the sliding mechanism is provided below the scanner and above the copy tray, the height of the image forming apparatus is relatively high. The finger wedging risk mentioned above is not eliminated.
JP-A 2006-119474 discloses a cavity type image forming apparatus in which the scanner is pivoted and copy sheets are discharged to the copy tray from the rear side of the apparatus. Therefore, when a small-size copy sheet is produced, the copy sheet on the copy tray cannot be absolutely observed from the front side of the apparatus because the exit of the copy tray is located on a relatively high level compared to the copy discharging exit through which copy sheets are discharged to the copy tray from the main body. In addition, a receiving material sheet on which an image is to be formed is fed from a lower side of the apparatus to the copy tray through the rear side of the apparatus. Therefore, when jamming occurs, it is not easy to remove the jammed sheet from the apparatus. Particularly, in a case where a small-size copy sheet is jammed, the jammed sheet cannot be accessed unless the scanner is opened while pivoted. In addition, the finger wedging risk mentioned above is not eliminated.
JP-A 2005-182032 discloses a cavity type image forming apparatus in which the scanner is pivoted and copy sheets are discharged to the copy tray from the rear side of the apparatus. Similarly to the image forming apparatus disclosed by JP-A 2006-119474, a small-size copy sheet on the copy tray cannot be absolutely observed from the front side of the apparatus. In addition, it is difficult to take such a small-size copy sheet from the copy tray unless the scanner is opened while pivoted. Thus, it is troublesome to take a copy sheet from the copy tray. When the space between the copy tray and the scanner is widened to improve the copy visibility, the height of the apparatus is increased. In addition, the finger wedging risk mentioned above is not eliminated.
JP-A 2004-264500 discloses a cavity type image forming apparatus in which copy sheets are discharged to the copy tray from one of the side portions of the apparatus while the scanner can be slid from the front side to the rear side thereof and vice versa. Although an openable and closable window is provided on an upper support of the image forming section to improve the copy visibility, copy sheets on the tray cannot be accessed unless a hand is inserted from the side of the apparatus, and it is troublesome to take out the copy sheet. In addition, the operation panel of the apparatus which is provided on the upper unit extends toward the operator side, and therefore the copy visibility and the copy accessibility are not good. Further, the finger wedging risk mentioned above is not eliminated. Furthermore, there is a risk such that an operator sprains his or her fingers when taking copy sheets from the copy tray.
JP-A 10-290311 (i.e., Japanese patent No. 3477026) discloses an image forming apparatus which is not a cavity type image forming apparatus and in which a scanner unit located over the printer unit is slid in the left and right direction. The finger wedging risk mentioned above is not eliminated.
In addition, JP-A 10-63053 (i.e., Japanese patent No. 3446928) discloses an image forming apparatus, which is not a cavity type image forming apparatus and in which a scanner unit located over the printer unit is slid in the left and right direction. The apparatus includes rollers configured to slide the scanner, roller shafts configured to support the rollers, and grooves configured to guide the roller shafts, in order to slide the scanner.
JP-A 2004-354832 discloses a cavity type image forming apparatus in which a scanner located over the image forming section can be smoothly slid without widely changing the center of gravity of the image forming apparatus. The image forming apparatus has such configuration that the image forming section and the scanner are supported by bosses and rails provided on the frame of the scanner, and rail guides and bosses provided on the upper surface of the image forming section.
In the image forming apparatuses disclosed by JP-As 10-63053 and 2004-354832, the number of parts increases, resulting in increase of the manufacturing costs, and the height of the apparatuses tends to increase.
Because of these reasons, a need exists for a cavity type image forming apparatus which has good copy visibility and which hardly causes problems in that fingers of operators are wedged between the scanner and the image forming when the scanner is slid, and goods such as clips are mistakenly dropped into the sliding mechanism, thereby damaging the sliding mechanism and the image forming apparatus. In addition, a need exists for a cavity type image forming apparatus which does not cause a problem in that when a user transports the apparatus while grasping the upper unit thereof, the upper unit is separated from the lower unit (such as image forming section) or the upper unit is deformed.